SYNOPSIS
--------
[verse]
-'git-filter-branch' [--env-filter <command>] [--tree-filter <command>]
+'git filter-branch' [--env-filter <command>] [--tree-filter <command>]
[--index-filter <command>] [--parent-filter <command>]
[--msg-filter <command>] [--commit-filter <command>]
[--tag-name-filter <command>] [--subdirectory-filter <directory>]
[--original <namespace>] [-d <directory>] [-f | --force]
- [<rev-list options>...]
+ [--] [<rev-list options>...]
DESCRIPTION
-----------
be able to easily push and distribute the rewritten branch on top of the
original branch. Please do not use this command if you do not know the
full implications, and avoid using it anyway, if a simple single commit
-would suffice to fix your problem.
+would suffice to fix your problem. (See the "RECOVERING FROM UPSTREAM
+REBASE" section in linkgit:git-rebase[1] for further information about
+rewriting published history.)
Always verify that the rewritten version is correct: The original refs,
if different from the rewritten ones, will be stored in the namespace
This is the filter for rewriting the commit's parent list.
It will receive the parent string on stdin and shall output
the new parent string on stdout. The parent string is in
- a format accepted by linkgit:git-commit-tree[1]: empty for
+ the format described in linkgit:git-commit-tree[1]: empty for
the initial commit, "-p parent" for a normal commit and
"-p parent1 -p parent2 -p parent3 ..." for a merge commit.
--commit-filter <command>::
This is the filter for performing the commit.
If this filter is specified, it will be called instead of the
- linkgit:git-commit-tree[1] command, with arguments of the form
+ 'git-commit-tree' command, with arguments of the form
"<TREE_ID> [-p <PARENT_COMMIT_ID>]..." and the log message on
stdin. The commit id is expected on stdout.
+
You can use the 'map' convenience function in this filter, and other
convenience functions, too. For example, calling 'skip_commit "$@"'
will leave out the current commit (but not its changes! If you want
-that, use linkgit:git-rebase[1] instead).
+that, use 'git-rebase' instead).
++
+You can also use the 'git_commit_non_empty_tree "$@"' instead of
+'git commit-tree "$@"' if you don't wish to keep commits with a single parent
+and that makes no change to the tree.
--tag-name-filter <command>::
This is the filter for rewriting tag names. When passed,
The result will contain that directory (and only that) as its
project root.
+--prune-empty::
+ Some kind of filters will generate empty commits, that left the tree
+ untouched. This switch allow git-filter-branch to ignore such
+ commits. Though, this switch only applies for commits that have one
+ and only one parent, it will hence keep merges points. Also, this
+ option is not compatible with the use of '--commit-filter'. Though you
+ just need to use the function 'git_commit_non_empty_tree "$@"' instead
+ of the 'git commit-tree "$@"' idiom in your commit filter to make that
+ happen.
+
--original <namespace>::
Use this option to set the namespace where the original commits
will be stored. The default value is 'refs/original'.
-f::
--force::
- `git filter-branch` refuses to start with an existing temporary
+ 'git-filter-branch' refuses to start with an existing temporary
directory or when there are already refs starting with
'refs/original/', unless forced.
-<rev-list-options>::
- When options are given after the new branch name, they will
- be passed to linkgit:git-rev-list[1]. Only commits in the resulting
- output will be filtered, although the filtered commits can still
- reference parents which are outside of that set.
+<rev-list options>...::
+ Arguments for 'git-rev-list'. All positive refs included by
+ these options are rewritten. You may also specify options
+ such as '--all', but you must use '--' to separate them from
+ the 'git-filter-branch' options.
Examples
A significantly faster version:
--------------------------------------------------------------------------
-git filter-branch --index-filter 'git update-index --remove filename' HEAD
+git filter-branch --index-filter 'git rm --cached filename' HEAD
--------------------------------------------------------------------------
Now, you will get the rewritten history saved in HEAD.
+As with using `rm filename`, `git rm --cached filename` will fail
+if the file is absent from the tree of a commit. If it is not important
+whether the file is already absent from the tree, you can use
+`git rm --cached --ignore-unmatch filename` instead.
+
+To rewrite the repository to look as if `foodir/` had been its project
+root, and discard all other history:
+
+-------------------------------------------------------
+git filter-branch --subdirectory-filter foodir -- --all
+-------------------------------------------------------
+
+Thus you can, e.g., turn a library subdirectory into a repository of
+its own. Note the `\--` that separates 'filter-branch' options from
+revision options, and the `\--all` to rewrite all branches and tags.
+
To set a commit (which typically is at the tip of another
history) to be the parent of the current initial commit, in
order to paste the other history behind the current history:
as their parents instead of the merge commit.
You can rewrite the commit log messages using `--msg-filter`. For
-example, `git-svn-id` strings in a repository created by `git-svn` can
+example, 'git-svn-id' strings in a repository created by 'git-svn' can
be removed this way:
-------------------------------------------------------
To restrict rewriting to only part of the history, specify a revision
range in addition to the new branch name. The new branch name will
-point to the top-most revision that a 'git rev-list' of this range
+point to the top-most revision that a 'git-rev-list' of this range
will print.
*NOTE* the changes introduced by the commits, and which are not reverted
by subsequent commits, will still be in the rewritten branch. If you want
to throw out _changes_ together with the commits, you should use the
-interactive mode of linkgit:git-rebase[1].
+interactive mode of 'git-rebase'.
Consider this history:
---------------------------------------------------------------
+
+Checklist for Shrinking a Repository
+------------------------------------
+
+git-filter-branch is often used to get rid of a subset of files,
+usually with some combination of `\--index-filter` and
+`\--subdirectory-filter`. People expect the resulting repository to
+be smaller than the original, but you need a few more steps to
+actually make it smaller, because git tries hard not to lose your
+objects until you tell it to. First make sure that:
+
+* You really removed all variants of a filename, if a blob was moved
+ over its lifetime. `git log \--name-only \--follow \--all \--
+ filename` can help you find renames.
+
+* You really filtered all refs: use `\--tag-name-filter cat \--
+ \--all` when calling git-filter-branch.
+
+Then there are two ways to get a smaller repository. A safer way is
+to clone, that keeps your original intact.
+
+* Clone it with `git clone +++file:///path/to/repo+++`. The clone
+ will not have the removed objects. See linkgit:git-clone[1]. (Note
+ that cloning with a plain path just hardlinks everything!)
+
+If you really don't want to clone it, for whatever reasons, check the
+following points instead (in this order). This is a very destructive
+approach, so *make a backup* or go back to cloning it. You have been
+warned.
+
+* Remove the original refs backed up by git-filter-branch: say `git
+ for-each-ref \--format="%(refname)" refs/original/ | xargs -n 1 git
+ update-ref -d`.
+
+* Expire all reflogs with `git reflog expire \--expire=now \--all`.
+
+* Garbage collect all unreferenced objects with `git gc \--prune=now`
+ (or if your git-gc is not new enough to support arguments to
+ `\--prune`, use `git repack -ad; git prune` instead).
+
+
Author
------
Written by Petr "Pasky" Baudis <pasky@suse.cz>,